Paper products are routinely formed using one or more ultraviolet-activated materials, such as fluorescent materials. These ultraviolet-activated materials can serve a wide variety of purposes. For example, fluorescent whitening agents (“FWAs”) are often added to paper in order to increase the “whiteness” appearance of the paper. Also, fluorescent materials are often added to paper for security purposes. For instance, visible or invisible ultraviolet-fluorescent fibres, pigments, highlights, and planchettes are often added to paper for use in the authentification of paper documents. As particular examples, invisible and visible fibers can be added to paper in an array of colors, lengths, and densities. Also, small particles can be added to paper in order to create highlights that have visible, visible fluorescent, or invisible fluorescent colors. Planchettes represent very small discs that can be embedded into paper during production and are available in visible, visible fluorescent, and invisible fluorescent colors.
Fluorescent materials can be used in various other ways. For example, fluorescent materials could be used to determine the “goodness” of the bonding of a specific material onto fibers or fillers in a papermaking system. This goodness is commonly quantified as a paper substrate's “retention” when discussing the wet-end process of the papermaking system. Fluorescent materials may also be used to analyze the goodness of mixing processes in the papermaking system. In addition, fluorescent materials can be activated by the presence of specific chemicals in the wet-end process of the papermaking system.